Infidelity does happen, but it's much much less common and is severely looked down upon. Edit: it seems that HSV-1 is not an STD, but it causes genital herpes

Infidelity does happen, but it's much much less common and is severely looked down upon. Edit: it seems that HSV-1 is not an STD, but it causes genital herpes if engaging in oral sex? Which can explain the big gap between the two in conservative cultures.